The present invention relates to an electrical unit having a housing or housing part and a first and a second printed circuit board which can be placed in contact with one another so as to be electrically conductive, and to a housing or housing part for an electrical unit, provided for accommodating a first printed circuit board and a second printed circuit board which can be placed in contact with the latter.
To connect components of electrical and/or electronic assemblies, e.g., the aforementioned two printed circuit boards, which are to be handled by the user, plug connectors with increasingly smaller contact spacings are used. This results both from the constant miniaturization of such assemblies and from modern production technology (use of SMT components).
This necessitates finer and more precise mechanical guidance of the components (on the aforementioned printed circuit boards) with respect to one another so that the plug connectors are not damaged when the assembly components are moved or so that the plugging procedure is made less complicated for the user and demands less sensitivity from him.
If the assembly components i.e.,xe2x80x94the printed circuit boards or the components of the electrical unit with the printed circuit boards it containsxe2x80x94are not plugged in only linearly, and hence in the plug connector""s direction of actuation, but are pivoted, this problem area becomes more intense.
Conventionally to mount the printed circuit boards in the components which hold the plug connectors which are to be connected, narrow tolerances are used so that their guidance is thus ensured. The components"" housings in turn have a guidance imparted relative to one another which is also provided with narrow tolerances. This ensures that, when the assembly components are plugged together, the plug connectors are brought into a position relative to one another which results in reliable plugging, and hence causes the contacts to be guided relative to one another without the possibility of any external influence.
In this case, the simultaneous action of various measures causes the resultant overall tolerances to become very large in comparison to the play of the plug connector used. This means that, on the one hand, complex measures are necessary to restrict the individual tolerances, particularly for the housing parts, and, on the other hand, the plug connectors used for this application need to have a certain xe2x80x9ccoarsenessxe2x80x9d.
Accordingly, an object of the present invention is to provide an electrical unit or a housing or housing part in which the mechanical guidance of the components relative to one another is shifted from the plane of the housing to the plane of the printed circuit board.
This object is achieved by providing a housing or housing part which at least one aligning element suitable for guiding and fixing both a first and a second printed circuit board, in that the first printed circuit board with a cutout which is matched to the cross section of the aligning element and through which the aligning element protrudes when the first printed circuit board has been fixed, and a free end of the aligning element with a contour which acts to guide the second printed circuit board when contact is made with the latter.
Similarly, the aforementioned object is achieved by providing a housing or housing part with at least one aligning element suitable for guiding and fixing both the first and the second printed circuit board, the aligning element engaging in a cutout, which is matched to the cross section of the aligning element, in the first printed circuit board in order to guide and fix the first printed circuit board, and a free end of the aligning element with a contour which acts to guide the second printed circuit board when contact is made with the latter.
The contour, above-described, of the free end of the aligning element can, for example, be a slot-shaped contour, with the slot being oriented parallel to a plane defined by the plug connector on the first printed circuit board, so that the second printed circuit board can be aligned by this contour of the aligning element at least in relation to one direction of movement.
If the second printed circuit board has a guide contour which engages with the contour of the aligning element when contact is made between the second printed circuit board and the first printed circuit board, the second printed circuit board is guided exactly in two directions of movement when contact is made with the first printed circuit board. This means that, when contact is made with the first printed circuit board, the second printed circuit board is guided by the aligning element in the two directions of movement perpendicular to the plug connector""s direction of actuation.
If the aligning element is integrally formed on the housing or housing part, the fact that the aligning element is undetachably connected to the housing means that the components can be guided particularly exactly.
If the aligning element is tapered toward the free end, alignment of the first printed circuit board by means of the cutout, which is matched to the cross section of the aligning element, in this printed circuit board is simplified.